For the second time in two days, an American Airlines flight was forced to make an emergency landing when passengers and crew members fell ill and lost consciousness in mid-flight.

The most recent incident involved a flight from Rio de Janeiro to Miami on Thursday carrying over 200 passengers and 14 crew at an altitude of more than 30,000’ forcing the pilot to change direction and request permission for the emergency landing in Brasilia.

Passengers said they feared for their lives when they saw people becoming ill, but paramedics who met the plane and examined four people, one passenger and three crew, determined they were not in need of further medical care or hospitalization.

The plane is a Boeing 777, the same model that encountered a similar incident on Wednesday, when 15 people became ill on a flight from London to Los Angeles, forcing the pilot to return to Heathrow Airport.

American Airlines released a statement calling the actions, “an abundance of caution,” and assuring the public that, “our maintenance team is currently inspecting the aircraft and performing a thorough maintenance check,” but it was unclear if the check pertained only to the two planes involved, the Boeing 777s, or the entire American Airlines fleet.

Although the airline said in its statement that passengers were being accommodated until travel arrangements could be made for them, tweeted, “Emergency landing in Brasilia from Rio to Miami. We’re all still waiting for an update on when we are flying back…” later updating, “Stuck in Brasilia for six hours with no food, no room, no help at all.”

Another frustrated passenger wrote in an email, “It sounds exactly like what happened on the other flight with us not being allowed off the plane for two hours,” calling the situation on the group “frustrating chaos.” That passenger reported in her email that a crewmember was overheard to say that the cause might have been “oven cleaner reacting badly.”

It is unknown if the National Transportation Safety Board (NTSB) or the Federal Aviation Agency (FAA) will become involved in formal investigations of the two incidents.